"I think I hear a catbird," he said. He mimicked the song, which at one point included a "meow."

Me, I just heard a siren, and maybe some traffic from the Eisenhower. But Gyllenhaal can hear past the sounds of the city to the sounds of birds. He is an urban birder in his element: Columbus Park on the city's Far West Side.

Columbus Park is one of the city's "underbirded" parks, to use birders' delightful term. Though it is a large expanse of nature, its inland location keeps it off most birders' radars.

"There are parks like Montrose and Jackson that a lot of birders go to because they're right on the lake," said Gyllenhaal, a naturalist and museum consultant from Oak Park.

It is a rational choice: The lakefront is a natural flyway. Migrating birds follow the shoreline and drop down to rest in spots like the Magic Hedge at Montrose Point. Lakefront parks can get 200 or more species of birds a year.

"But the thing is, there are these parks eight or 10 miles inland that people don't pay as much attention to, and we'll wind up getting 150 species," said Gyllenhaal, who with his two sons has been tallying birds at Columbus Park since 2007.

Underbirded parks offer freedom from traffic and plenty of parking. And, for many people, they are more convenient than the lakefront. Gyllenhaal can walk to Columbus from his Oak Park home.

Parks like Columbus, Jackson, Garfield, Douglas and Humboldt are excellent bird habitats, he said. "One thing they put in when they were first built is lagoons," he said. "Just having open water will attract ducks, geese and herons.

"Then there are plants growing around that, marshy plants like cattails, and the wooded margins. They'll attract marsh sparrows and wrens. The trees will get a lot of warblers and other kinds of sparrows. Scarlet tanagers will go to trees around lagoons."

And the Chicago Park District's removal of invasive plants and planting of native ones has attracted more birds, he said.

Humboldt Park is similarly bird-friendly, said Sam Burckhardt, a board member of the Chicago Ornithological Society, but it is off the radar for most Chicago birders.

He started going because it is close to his East Village home. He kept going — 62 times last year — because "it is a great park," he said.

Burckhardt, a jazz and blues musician, loves the lagoon, native wildflowers and naturalistic design; like Columbus and Garfield parks, Humboldt was designed in Prairie style by Jens Jensen. Burckhardt has seen a whooping crane migrating with a flock of sandhill cranes; a surf scoter, a duck rarely found away from Lake Michigan; and one spring, a disheveled-looking northern goshawk being harassed by about 40 cawing crows.

"If you really open up your eyes, you find good stuff everywhere," he said.

On this blustery morning in Columbus Park, Gyllenhaal's sons, Ethan, 15, and Aaron, 13, had found a black-throated blue warbler in Austin Woods. The patch of trees on the city's border with Oak Park is excellent for certain migrating warblers, "but you have to walk through a lot of trash," Eric Gyllenhaal said.

Aaron looked on the bright side. "The trash is sometimes as colorful as the birds," he said.

Indeed, urban birding has its gritty elements. As we walked through the park, we saw the Red-Banded Mello Snack Bag, the Ubiquitous White Plastic Grocery Bag and the Common Condom.

"After dark this park is used for all sorts of things besides birding," Eric Gyllenhaal said.

Rambling through Columbus Park behind the rectory, a charming spot with nodding orange columbine, a meandering path along the lagoon and a limestone waterfall, I saw a ruby-crowned kinglet, a green heron and an American redstart.

The experienced Gyllenhaals (and yes, they are related to Jake and Maggie) saw far more. And as we circled back to the refectory, Ethan looked up into the open sky, where some 50 small birds were swooping.

"Oh, wow — chimney swifts," he said.

The day's list: 72 species, a typical walk in a city park.

If you go

Go with experienced birders. It takes practice to hear, see and identify birds.

An ideal outing

Humboldt Park, 6:30 a.m. Saturday. Sam Burckhardt will lead a field trip in the Chicago Ornithological Society's continuing series, Underbirded Chicago Parks. Meet at the parking lot at the field house, which is on the west side of Humboldt Park Boulevard, south of North Avenue and north of Division Street.